1. Field of the Invention
The present invention relates to electric power generation systems and, more specifically, to a hybrid solar power and mechanical power generating system.
2. Description of the Related Art
There are generally three different sources for scavenging energy from the environment: solar energy, thermal energy and mechanical energy (such as wind energy). Solar cells are typically used to collect solar energy and transform it into electrical energy. However, solar cells cannot produce electricity at times when there is insufficient ambient light, such as in the evening.
Mechanical energy, from large-scale winds to micro-scale vibration, is almost always available. Thus, a system for converting mechanical energy to electricity would be able to produce electricity almost anywhere at almost any time.
Recently, a ZnO nanowire-based nanogenerator that can effectively convert small scale mechanical vibration energy into electricity has been demonstrated. However, the power output of the nanogenerator was relatively low in some applications.
The highest efficiency solar cells to date (40.7%) employ optical lenses to focus light onto the photovoltaic materials. These concentrators are expensive and have therefore been limited in scalability.
Driven by the telecommunications industry, there has been a tremendous amount of research in the past two decades into fiber optic cables as a medium for transporting data in the form of light. At present, a mature infrastructure is in place for mass production of optical fibers. State-of-the-art fibers can transport light up to distances of 500-800 km with low signal attenuation owing to the physical principle of total internal reflection. Given these characteristics, fiber optic cables are potentially an ideal medium for directing light towards a photovoltaic material system for solar energy harvesting.
Therefore, there is a need for a hybrid nanogenerator that combines a highly efficient solar cell with a piezoelectric nanogenerator that can generate power continuously in a range of different and changing environments.
There is also a need for a scalable optical system which can transport the light energy to the photovoltaic elements.